1. Technical Field
The disclosure in generally relates to a display device and more particularly to a liquid crystal display (LCD).
2. Description of the Related Art
Currently, the design of LCDs is trending towards to offer high luminance, high contrast ratio and wide viewing angle. Several technologies for improving the viewing angle of an LCD have been provided to satisfy the design requirements. A multi-domain vertical alignment liquid crystal display (MVA LCD) is a common type of LCD with wide viewing angle.
A MVA LCD typically has a plurality of alignment protrusions or slits disposed above a substrate with thin film transistor (TFT) array formed thereon, and used to direct the liquid crystal molecule tilting in various directions, whereby a plurality of alignment domains, e.g. alignment domains R1, R2, R3, R4, R5, R6, R7 and R8 as shown in FIG. 1, are obtained. When different voltages are applied, the liquid crystal molecule may be tilted in various angles to make images that are observed by a user from different view angles has identical phase difference. Such that an LCD with wide viewing angle can be implemented.
However, the transmittance of the MVALCD may vary at different view angles. As a result, color shift may occur and chroma (saturation) of the MVA LCD may be deteriorated.
In order to solve these problems, the pixel electrode 101 of a conventional MVA LCD 100 is divided into at least two independent sub-pixel electrodes, such as two independent sub-pixels electrode 101a and 101b (as shown in FIG. 1), respectively controlled by different active elements 102 and 103 are provided. By applying two different voltages to these two independent sub-pixels 101a and 101b respectively to make the LCD molecules overlying thereof tilting in different angles and form a plurality of alignment domains, the problems of color shift and chroma deterioration can be significantly improved.
But this approach still has some drawbacks. In the conventional MVA LCD 100, the electrode 103a of the active element 103 typically extends across the sub-pixel electrode 101a and electrically connects to the sub-pixel electrode 101b through a via hole 104 formed at the center of the sub-pixel electrode 101b. In order to prevent light leaking from the via hole 104, a patterned metal layer 105 with a size substantially larger than that of the via hole 104 is generally formed on the position where the via hole 104 connected to the sub-pixel electrode 101b. Such that, the aperture ratio of the pixel electrode 101 can be decreased due to the shielding of the patterned metal layer 105.
Therefore, there is a need of providing an improved LCD to obviate the drawbacks encountered from the prior art.